Vehicles with internal combustion engines may utilize a laser system in the engine in various ways.
For example, U.S. Pat. No. 7,532,971 B2 describes a system including an engine control apparatus designed to control pilot injection timing based on a heat generation quantity and a fuel supply quantity in order to increase the combustion rate. An ignition device which relies on the use of an electric heater (glow plug) or an electromagnetic action such as a laser for locally shifting the energy level of an in-cylinder atmosphere to a higher side to thereby facilitate ignition, is also described.
The inventors herein have recognized various issues with the above system. In particular, raising the energy level of the in-cylinder atmosphere with the laser may cause ignition earlier than desired under some conditions where too much energy is provided. Likewise, providing too littler energy may be insufficient to obtain reliable compression ignition.
As such, one approach to address the above issues is to focus the laser energy at different locations within the cylinder. By changing the focus location for different actions, one location for ignition and a second, different, location for heating (such as the peripheral cylinder wall), for example, it is possible to obtain reliable ignition while also achieving more rapid engine warm-up, and thus reduced friction. Furthermore, the laser operation at the first location may be performed at a different timing of the combustion cycle. In this way, the combustion cylinder wall may be heated at a time without interfering with ignition timing.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.